The present invention relates to railroad systems, and more particularly, to a system and method for measuring a distance within a railroad system. In railroad systems, such as those including a locomotive traveling along a pair of rails, for example, various distance parameters should be monitored to ensure proper operation of the railroad system. The monitoring of these distances have varying applications. For example, when a locomotive is reversing toward an object positioned in the reversal direction, the distance between the back end of the locomotive and the object should be monitored to ensure that the locomotive does not make unintended contact with the object. In another application of monitoring distance parameters during the operation of a railroad system, relative distance shifts of the rails during operation of the railroad system may be monitored to guard against possible derailment.
As illustrated in FIG. 1, in conventional railroad systems, a truck 11 is employed to travel over a pair of rails, and includes a phased array 13 (FIG. 2) adjacent an undersurface of the truck 11 which is contacted against a respective rail 15 as the truck 11 travels over the pair of rails. As shown in FIG. 3, the phased array 13 of the truck 11 emits a plurality of radio frequency signals 17, which subsequently deflect from an imperfection 19 within the rail 15 and are detected by a detection mechanism 21. Although FIG. 3 illustrates an imperfection 19 located within one particular location of the rail 15, the imperfection 19 may be located at any location within the rail 15. Once the truck 11 has finished traveling over the rail 15, data supplied from the detection mechanism 21 provides a detailed analysis of imperfections 19 within the rail 15 at each location along the rail 15.
Although conventional railroad systems provide a truck (or similar vehicle) to travel over a pair of rails and provide a detailed analysis of the imperfections within the rail, such railroad systems neither provide an analysis of relative distance shifts of the rails as an indication of possible derailment, nor provide such an analysis under real operating conditions. Thus, it would be advantageous to provide a system for measuring distances related to the locomotive traveling along the rail under real locomotive operating conditions.